There are many applications in industry which require the joining of two tubular bodies such as pipes, canisters and the like for containing fluid under pressure. Many of these applications require a joint which can be readily opened or disassembled for purposes of maintenance or repair. An example is that of vehicle engine exhaust systems wherein several different exhaust system components such as mufflers, catalytic converters, particulate filters and pipes are coupled together for discharging the exhaust gases to the atmosphere. In exhaust systems, the typical components are round or roundish in cross-section and the joints must provide a good fluid seal against exhaust gas leakage. Also, the joints must exhibit a high degree of mechanical strength for withstanding road shock and vibration without loosening and without impairment of the sealing properties of the joint.
In some applications, a joint must be provided between components which are substantially larger in girth than that of the pipes which are typically used between components such as mufflers and catalytic converters. This may involve either lap joints or butt joints, either of which may utilize circumferential ribs or beads to provide a positive mechanical engagement of the coupler with the components being joined. For configurations such as this where a rib or bead is used, various band clamp arrangements have been proposed. V-band clamps are well known, and different examples of these are shown in U.S. Pat. No. 2,731,280 to Goodliffe et al., U.S. Pat. No. 5,411,162 to Koziczkowski et al., and U.S. Pat. No. 6,073,977 to Schmidt-Hansen et al. As shown in the last of these, a rubber seal can be included that spans the two beads. Band straps having spaced circumferential ribs are also known for use in connecting sheet metal pipes. See U.S. Pat. No. 3,207,538 to Pattillo. The draw band disclosed therein comprises an open loop in which the ends overlap each other when the band is tightened. Such an arrangement results in a discontinuous step at the inner terminal end of the band and can be problematic for applications where a strong hermetic seal is needed such as in vehicle exhaust systems. This can be true even where a gasket is provided since the gasket is not subjected to uniform inwardly radial pressure at the inner terminal end of the band.
Therefore, it is a general objective of this invention to provide an improved band clamp which overcomes certain disadvantages of the prior art.